As opposed to standard formulations of equations of this type, our derivation of the Ehrenfest relations was performed entirely within the framework of ED, using Hamiltonians, Poisson brackets, etc., rather than commutators and the standard quantum machinery. These methods, which are geometric in nature, are thus of more general applicability than the standard techniques, which rely heavily on the linearity of quantum theory. Indeed, while the assumption of linearity has thus far proved quite robust, it is not immediately obvious that quantum gravity needs to follow suit (see e.g., [1]}[2]}-[3]}). In such cases the ED approach might provide a viable alternative framework.
